Ignition rotor with resistor



0 J. T. FITZSIMMONS 2,509,094

IGNITION ROTOR wrm RESISTOR Filed Dec. 6, 1947 Jam I firzsmmous ms HTWSRNEYS Patented May 23, 1950 UNITED STATES PATENT OFFICE IGNITION ROTOR WITH RESISTOR John T. Fitzsimmons, Anderson, Ind., assignor to General Motors Corporation, Detroit, Mich., a

corporation of Delaware Application December 6, 1947, Serial No. 790,112

Another object of the present invention is to i Figs. 1 and 2 are plan and side views, respec-' tively, of the rotor embodying the present invention.

Fig. 3 is an end view of the leaf spring conductor shown in Fig. 1 on an enlarged scale.

Figs. 4, 5 and 6 are views of the leaf spring conduction looking in the direction of arrows 4, 5 and 6 respectively of Fig. 3.

Fig. 7 is a view like Fig. l on an enlarged scale with the leaf conductor spring removed Figs. 8, 9, 10 and 11 are sectional views taken on lines 8-8, 9-9, Ill-l0 and ll-ll, respectively, of Fig. 7.

Referring to the drawings 20 designates a rotor body or block formed of insulating material, preferably of molded Bakelite, or similar material. The body is formed with a recess 2| having a lug 22 therein which forms the driving connection for the body when it is fitted over the end of a cam shaft, not shown. The cam shaft has a slot which receives the lug 22. The upper face of the rotor is formed with a pair of elongated parallel bosses 23 and a projection 24 located between the bosses. Before molding the body in its final form, a resistance element 25 of carbon or other suitable material having a high value of distributed resistance is placed in the mold cavity. In this instance the resistance element includes a lead 26 of Monel metal attached to one end thereof. It is to be understood that other metal which resists sparking can be used instead of Monel metal, for example nickel wire. The lead 26 of Monel metal is formed into a loop 21 which acts as a spark gap electrode.

It will be noted that the loop 21 is very close to the resistance element 25 and it also is relatively 3 Claims. (Cl. 201-46) small in dimensions. By having the lead 26 which provides the spark gap electrode as small as possible in dimensions as close as possible to the resistance element 25 the reduction of the effectiveness of the element 25 is practically negligible and radio interference will be substantially eliminated. The other end of the element 25 is connected by a copper lead 28 having its end 29 bent at an angle for connection purposes,

see Fig. 9. When the body 20 is formed about the element 25 the element will be partially embedded by a cover portion 30 and a portion of the lead 28 will also be embedded by a portion indicated at 3| but the end of the lead will be expoed above the plane surface of the block as indicated at 32. Thus, it will be seen that the resistance element 25 will be securely anchored to the body 20. The outer portion of the loop 21 extends slightly beyond the periphery of the body and acts as a spark gap electrode. A plurality of ridges 33 are provided on each side of the electrode 21 so as to give a long leakage path for the secondary current.

As mentioned heretofore the rotor is provided with the projection 24 and this projection is used to secure a leaf spring conductor or contact plate 35 with the body without the use of screws or rivets. In this instance one end of the leaf spring conductor is formed with a bowed portion 36 having an aperture 31. The bowed portion is sheared on opposite sides of the aperture so as to provide a pair of resilient fingers 39 the free ends of which extend slightly above the normal curvature of the bowed portion 36. The bowed end of the leaf spring is extended by an ear 4!! for connection with the end 29 of lead 28. The other end of the spring is bent upon itself and formed into a spherical contact 4| which is adapted to cooperate with the center contact of a distributor head, not shown, which is adapted to be connected to the coil of the ignition apparatus supplying high tension voltage.

When the leaf spring is mounted on the rotor body 20 the apertured bowed portion 36 is forced over the projection 24 causing the spring fingers 39 to be flexed. Flexing of the fingers 39 will be effective, upon release of the force, to grip the lug 24 and thereby prevent accidental longitudinal movement of spring relative to the body 20. The turning of the leaf spring 35 about the axis of the projection 24 is prevented by confining the side edges of the bowed portion between the elongated parallel bosses 23 on the rotor body 20. when the spring is assembled with the body the ear 4!! will lie over and engage the end 29. The ear 4!! is welded to the end 29 of the lead 28. By this arrangement the spark gap electrode 21 will be connected with the coil of the ignition apparatus through resistance element 25, lead 28, and the leaf spring 35.

It will be apparent from the foregoing description that the present structure can be adapted for various types of automotive engines since a resistance unit with the appropriate resistance desired may be inserted in the mold cavity before the body is molded in its final form. It will be noted that the resistance unit 25 is not entirely embedded in the body, as portions of the unit are exposed at certain places to provide for sufficient ventilation in air movements for cooling the resistance element.

The foregoing disclosure is to be regarded as descriptive and illustrative only and not as a restriction or limitation of the invention, of which obviously an embodiment constructed so as to include modifications without department from the general scope herein indicated and denoted in the appended claims will be permitted.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. An ignition distributor rotor comprising a molded block of insulating material, said block having an integral projection disposed between parallel lugs on the top face of the body; a spark gap electrode unit molded within said body, said electrode including a body of carbon having a relatively high value of distributing resistance, a lead of relatively soft metal having a portion exposed on the top face of the body and a lead of relatively hard arc resisting metal, said hard metal having an exposed portion extending slightly beyond the periphery of the body; a removable conductor of spring metal supported on the projection and disposed between the lugs whereby the lugs prevent the conductor from turning relative to the block; and means including portion of the conductor bearing against the exposed portion of the soft metal lead for electrically connecting the conductor with the electrodes.

2. An ignition distributor rotor comprising a body of molded insulating materiaihaving a pro" jection on the top surface thereof; a spark gap electrode unit molded in said both, said electrode including a body of carbon having relatively high value of distributing resistance, a lead of relatively soft metal having its extremity exposed on the top surface of the body and a lead of arc resisting material having a portion extending slightly beyond the periphery of the body; a leaf spring conductor having one end supported by the projection and having the other end adapted to engage a center contact of a distributor head, said first mentioned end of a spring having an ear bearing against the extremity of the soft metal lead to provide the electrical connection between the leaf spring and electrode; and means carried by the body to prevent turning of the spring conductor relative to the body.

3. An ignition distributor rotor comprising a molded block of insulating material, said block having an integral projection extending outwardly from the top surface of the body; a spark gap electrode unit molded with the body, said electrode including a body of carbon having a relatively high value of distributing resistance and a pair of metallic leads, one from each end of the carbon body, one lead having a portion exposed above the top surface of the body while the other lead has a portion exposed at the periphery of the block; a removable conductor of spring metal supported on the projection, said conductor having a portion bearing against the end of the lead terminating above the top surface of the block for electrically connecting the conductor with the electrode; and means including portions of the block to prevent turning of the conductor on the projection.

JOHN T. FITZSIMMONS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,925,856 Vaughan Sept. 5, 1933 1,931,625 Schwarze Oct. 24, 1933 1,997,460 Fitzsimmons Apr. 9, 1935 2,014,018 Dutterer Sept. 10, 1935 2,385,702 Hediger et al Sept. 25, 1945 FOREIGN PATENTS Number Country Date 496,982 Great Britain July 1, 1938 

